Fluid-pressure brake



APril 2, 1929- T. H. THOMAS ET AL 1,707,289

FLUID PRE S SURE BRAKE Filed Nov 50, 1927 INVENTOR THOMANI;I.T HOMAS CLAUDE ANELso N ATTO EY Patented Apr. 2, 1929.

UNITED STATES PATENT OFFICE.

THOMAS H. THOMAS, 011 EDEtEWGOD, AND CLAUDE A. NELSON, F WILMEHDING, PENNSYLVANIA, ASSIC'rNORiE TO THE WESTINGHOUSE AIR, BRAKE COMPANY, OF WILMEBDING, PENNSYLVANIA, A CDRPGIEt-A'EION OF PENNSYLVANIA.

FL'UlllD-PREEZS'U 11E Application fil ed November 30, 192?, Serial No. 236,671.

This invention relates to tluidpressure brakes and more particularly to locomotive brake equipment ot the type having means for zuitoinatically c'tlecting an application of the brakes.

lin order to apply the brakes on a train in such a mannenas to avoid harsh or rough. gathering," of the slack between the cars, which might result in wrecking the train, the brake pipe reduction may be started at a predetermined. slow rate, so as to cause the train slack to be gently gal'herl-id, and litter the slack is thus nitherei'l the rate of reducing the brake pipepressure can be increased, so as to etl'ect the desired application oi the brakes.

()ne object of our im'ention to provide improved means for zmtoniatically effecting a brake pipe l(-5(ll1(ftl0ll at two different rates,

the initial predetermined degree oil such rekhutio-n to be made at a slow rate and the second portion of such reduction to be made at a taster rate. r i

In effecting a brake pipe reduction on a train having: a silbstmitially airtight brake pipe the rate of brake pipe reduction is nowyrned. by the brake pipe discharge valve, ivhich is opened by the eqrurlizinp; piston,

when the pressure in the equalizing reservoir is reduced below that in the brake pipe. l'lowever under some conditions, such as brake pipe leakage and depemlent upon the l ngth. oi the train, the brake pipe pressure acting on the equalizing piston may reduce at a faster rate than the equalizing; reservoir press'lu'e is reduced. This is undei-iirable particularly during-r the initial re duction, since too fast a rate of reduction in brake pipe pressure tends to cause a severe brake application and a consequent rough gathering of the train slack.

7 Another object of our invention is to provide improved. means For preventing the lN'illIO pipe pressure from riulucing at a greater rate than would be effected by operation of the eqini-lizing discharge valve mechanism.

After the train slack is gathered, the brake pi pe pressure can be reduced at a inorerapid rate than duringthe initial reduction, so that under such conditions it is not so neressary to prevent the brake pipe pressure from reducing faster than the equalizing reservoir pressure is reduced. Fultheripore" x after the brakes are fully applied, it is undesirable to have the brake pipe pressure lnit the rate of the second port-ion of the brake pipe reduction to be governed by the effect of brake pipe leakage in addition to the opening past the brake pipe discharge alvc, in order to prevent the undesired rclease o'lf' brakes, in the manner described. above.

The severity of slack action in a train decreases in proportion to the decrease in train length, so that the rate of effecting a brake length decreases.

Another object of our invention is to provide manually controlled means tor varying the rate of effecting a reduction in equalizing reservoir pressure, in accordance with the train length.

Other objects and advantages Will appear in the following more detailed description oi our invention.

in the accompanying drawing, the single tigure i s a diagrammatic view of a fluid pres sure train control apparatus embodying our invention.

As shown in the d rawiug, the train control apparatus comprises an automatic brake valve device 1, a magnet valve device 2 and a feed valve device 3.

The automatic brake valve device conip rises a casing having a chamber 4 containing a rotary "valve 5 adapted to be operated by a handle 6 and an equalizing valve mechanism (Hi'liiH'lSlUg a diaphragm 7, having at one side a chamber 8 connected to an equalizing reservoir by means to be hereinafter described and having at the opposite side a valve chamber 9 connected to a brake pipe ll) through a ciassanc 11. The valve chamber 9 contains a slide valve 12 disposed between two shoulders on the stern of a diaphragm head 13, which head secured to the diapipe reduction can be increased as the train phragm 7. A chamber 14 is separated from the valve chamber 9 by an apertured washer 15 having screw-threaded engagement in the wall of the valve chamber 9.. A spring retainer 16 isadapted to operate through the aperture in the washer 15 and the movement hold the retainer shoulder 16 in engagement With the w asher 15, in which position the stem of the di aphragm head 13 is adapted to cnga'aeth'e retainer and thus maintain the equalizing slide valve 12 in its normal release position, as shown in the drawing.

A reduction regulating valve mechanism is alsodisposed in the brake valve casing and comprises a diaphragm 18, having at one side a chamber 19, which is connected to a reduction regulating reservoir through a passage and pipe 20, and having at the opposite side a chamber 21, which is connected tothe equalizing diaphragm chamber '8 through apassage 22, and which is also con nected to anequalizing reservoir through passage and pipe 23. The chamber 21 con tains a diaphragm head 2 iadapted to be held in engagement with the diaphragm 18 by the pressure of. a spring 25. A valve 26, contained in a chamber 27, which chamber is connected to 'a reduction limiting reservoir -through a passage and pipe 28, has a stem 29'eXt-ending through an opening in the casing wall and into the eiaphrag'm head chamber 21, wherein such valve stem is adapted to be engaged by the depending stem 30 ot' the diaphragm head 24,-. The valve stem 2?) is provided with a port 31, which port is adapted to permit communication between chamber'21 and chamber 27, when the valve 26 is unseated, but when such valve is seated by the pressure of a spring;- 32, contained in the chamber 27, suchcommunication is cut off. I A double beat valve 83 is contained in av chamber 34', which is connected to the seat of the equalizing slide valve by passage 35, andsaid valve has at one side a solid stem 36 extending through awvall of the casing into the-valve chamber 27, wherein such. stem adapted'to'be engaged by the valve 26. The double beat valve has at the opposite side a fluted stem 37 extending; through a wall of the easing into a chamber 38,whercinfa spring 89 engages a thrust washer 40 mounted on the valve stem 37, and tends to seat the double'beat valve 3?) in the upward positiom'as shown in the drawing.

The casing of the brake'valve device also contains acutotl valve mechanism comprisin a cut-otl' valve 41 contained in a chamber '42'and adapted in one position to seal on a seat ring A cut-oil valve piston ll, which is opcrativcly conncctcd to the culotl' valve 41 by a stem i5, is contained in :1 chamber 16, which chamber also contains a spring 47 acting: on the cut-elf valve piston.

A plug valve 418 is contained in a chamber in the brake valve device and is adapted to be operated by a handle 19. The plug: valve contains two restricted ports 50 and 51 of ditl'ercnt the port 50 being adapted to connectpassage 28 from the reduction limiting reservoir to a pas r30 52, whcn the valve operating handle 49 is in the position shown in the drawing. lVith the valve operating handle 49 in the position indicated by the line 53, the restricted port 51 com ccls pussaucs and 52.

Preferably associated with the brake valve device is a brake application valvc incchanism, which comprises a piston Til cozuaincd in a chamber and a slide valvc we contained in a valve chamber 57 and adapted to be operated by the piston 54. The piston chamber is connected through a purrtujc and pipe 58 to the magnet valve device .3 and contains a spring 59 tending to hold the piston 54 and slide valve 56 in the release position, as shown in the drawing.

The magnet valve device 2 comprises a magnet adapted to control the operation of a valve 60, which is urged away from its seat by a spring 61. The valve (30 is adayucd to control communication between the ap plication piston chamber 55 and the atmosphere, through passage and pipe 58 and the atmospheric exhaust pa sage (32. The magnet of the magnet valve device is adapted' to be controlled by train control appnrzp tus (not shown), in such a manner that when the train is operating in territory where the track conditions are favorable, such magnet is energized and operates to scat valve (K). but when operating in territm'y where the track conditions are unfavorable, the IHEILE net is dccncrgrizcd and the valve (30 is unscated by the spring 61.

In operation, fluid under pressure is supplied t'rom a main reservoir 63 to the rotary valve chamber 1-, to the application valve chamber 57 and to the feed valve dcvice 8 through pipe and passage (ll. Fluid from the application valve chamber thcn flows through a port 65 in the application piston 54: and into the application piston chamber 55 and from thence ilil'mr'l'li pussage and pipe 58 to the magnet valve device 2. lVith a train operating in tcriiiorv groverned by favorable track conditions, the mag:- net of the magnet valve device is energized. thereby seating valve 60, so that a fluid pressure builds up in the application piston chambcr55 equal to the pressure of the lluid in the application valve chamber 57. The pressure of spring 59 is thereby permitted to push and normally hold the application pisllll ton 54 and slide valve 56 in the release position, as shown in the drawing.

Fluid at the usual reduced pressureemployed in the brake pipe is supplied by the feed valve device 3 to the seatiot the rotary valve athrough pipe and passage 66. YVith the brake valve device in running position, as shown in the drawing, fluid at feed valve pressure flows from passage 66 to the cutotl valve piston chamber 46 by way of cavity 67 in the rotary valve passage 68, cavity 69 in the application slide valve 56, and passage 70. Fluid at feed valve pressure also flows from passage 68 into the cut-off valve chamber 42. With the brake system uncharged, the cut-off valve 41 is: unseated by the pressure of spring 47 and in charging, since the fluid pressure buildsup on the opposite sides of the cut-ofl valve piston 44: at the same time, the cutoff valve -11 remains unscated and permits fluid at feed valve pressure, to flow from chamber l2 to the brake pipe 10 through passage 71, the equalizing valve chamber 9 and passage 11, thereby charging the brake pipe.

Fluid at feed valve pressure also flows from cavity 67 in the rotary valve 5 to the equalizing reservoir and to the reduction regulating valve diaphragm chamber 2i by way of passage 72, cavit 1 73 in the applica tion slide valve 56 and passage and pipe 23 and from the diaphragm chamber 21 to the equalizing diaphragm chamber 8 through passage 22. The equalizing reservoir pressure and brake pipe pressure acting on the cqualizin diaphragm 7 thus bein substantially equal, the equalizing mechanism is held in the position shown in the drawing, in which position the stem of the diaphragm head 13 rests on the spring retainer 16.

Fluid at feed valve pressure also flows from cavity 7 3 in the application slide valve to the reduction regulating valve diaphragm chamber 19 and the reduction regulating reservoir by way 01 passage 20. The fluid pressures thus being substantially equal on the opposite sides of the reduction regulating diaphragm 18, the pressure of spring holds the diapl'iragm 18 and the diaphragm head 24: against the stop lug 81, in which position the valve 26 is seated by spring 32 and the double beat valve 33 is seated in the upper position, as shown in the drawing, by spring 39. \Vit-h the double beat valve 33 seated in the upper position, fluid at feed valve pressure is permitted to flow from cavity 73 in the application slide valve 56 to the seat oil the equalizing slide valve 12, through passage 74, spring chamber 88, past the fluted stem 37 of the double beat valve 33, through the double beat valve chamber 34 and from thence through passage With thebrake valve handle 6 in running position, the reduction limitingreservoir is connected to the atmosphere through pass sage 28, valve chamber 27, passage 7 5, cavity 76 in the rotary valve 5 and an atn'iosphcric exhaust passage 77.

If the track conditions become untavorable, the magnet of the magnet valve device,

2 becomes deenergized. The valve is then unseated by spring 61, which permits the fluid under pressure in the application piston chamber 55 to be vented, to the atmosphere through passage and pipe 58, and passage 62. The main reservoir pressure in the application valve chamber 57 then shiitts: the application piston 54: and slide valve 56 downwardly to application position, against the pressure of spring 59.

In application position oil" the application slide valve, the cut-off valve piston chamber 46 is vented to the atmosphere through passage 70, cavity 78 in the application slide valve and the atn'iospheric exhaust passage 79. The brake pipe pressure acting on the opposite side oi the cut-oil valve piston. il then sh itts the cut-oil valve piston and cutotl? valve 4-1 outwardly against spring 4L7, thereby seating the cutoff valve ll against the seat ring 43, so as to prevent further flow of fluid from the feed valve device to the brake pipe. The equalizing diaphragm chamber 8, the reduction regulating valve diaphragm chamber 21 and the equalizii'ig reservoir are connected to the reduction limiting reservoir through passage 23, cavity 73 in the application slide valve, passage 52, choked port 50 in theplug valve -18 and passage and pipe 28. The equalizing reservoir pressure is thereby permitted to reduce at aslow rate, as governed by the choked port 50. The higher brake pipe pressure, acting in the equalizing valve chamber 9, then. deflects the equalizing diaphragm 7 upwardly, which causes the equalizing slide valve 12 to partially uncover the restricted brake pipe discharge port 80 and permit fluid under pressure to flow from the brake pipe l'lllOllg'll passage 1.1, valve chamber S) and port 80 to the atmosphere, tl'iereby causing a brake pipe reduction at a rate governed by the slow rate of decrease in the equalizing reservoir pressure which is cll'ect-ive in diaphragm chamber 8. i

VVit-h the application slide valve 56 in application position, the passage 20 leading to the reduction regulating valve diaphragm chambcr19 and reduction regulating reservoir is lapped, so that when ell'ecti11g a lu'alto pressure from the equalizing reservoir to lOO flow to the reduction limiting reservoir through port 31 in the valve stem 29, in additionto the flow through the choked port 50 in the plug valve 48,, which latter flow continues as during the initial portion of the brake pipe reduction. This causes the equalizing reservoir pressure to reduce at a faster rate than the initial rate of reduction. Such faster rate of reduction belng effective in the equalizing d aphragm chamber 8 the totaldecrease in equalizing reservoir pressure 1s thereby limited to equalization It the into the reduction limitin reservoir. atmospheric connectlon or the reduction limiting reservoir is not lapped, then the equal-- izing reservoir fluid Will'be completely vented to the atmosphere and will permit the Y equalizing valve mechanism to completely vent the brake pipe.

If there is sufficient leakage of fluid under'pressure from the brake pipe to the atmosphere to cause the brake pipe pressure to reduce at a faster rate than the equalizing reservoir pressure is reduced, then the equalizing reservoir pressure becomes higher than the brake pipe pressure and deflects the equalizing diaphragm Tclownwardly, which causes the slide valve 12 to be shitted so as to uncover the passage 35. 'Vi ith the double beat valve33 seated in the upper position, as snown in the drawing, and the application slide'valve 56 in application position, the passage 35 is connected to the application slide valve chamber 57 through valve chamber 34, spring-chamber 38 and passage 74, so that fluid at main reservoir pressure is thereby permitted to flow from the application-valve chamber to theequalizing valve chamber 9' and from thence to brake pipe 10, thereby causing the pressure of brake pipe fluid to be increased. The brake pipe pressure can not be. increased to a degree higher than the reducing equalizing reservoir pressure-however, since when the brake pipe pressure becomes substantially equal to the equalizingreservoir pressure, the equalizing valve-mechanism operates to prevent further flow of main reservoir fluid to the brake pipe.

'In the manner just described, the brake pipe pressure: is maintained substantially equal to the p reducing equalizing reservoir pressure, as long as the double beat valve 33 remains seated in the-position shown in the vthe faster rate of drawing. At the end of the first portion of the reduction, the reduction regulating valve diaphragm 18 operates as hereiubeiiorc described, to unseat valve 26 in order to start 'eduction in equalizing reservoir pressure. Unseating of valve so seats the double beat valve 33 in the lowe position and thereby cuts oil connnunication between the spring chamber 38 and valve chamber so that during the second portion of the brake pipe reduction, it the degree of brake pipe leakage is such as to cause the brake pipe pressure to reduce faster than the equalizing reservoir pressure is reduced, fluid under pressure can not flow from the main reservoir to the brake pipe in order to maintain the rate of pressure drop therein, as during the initial portion of the reduction. This is desirable, because after the reduction in equalizing reservoir pressure is con'ipletcd, ii the brake pipe pressure is maintained equal to the reduced equalizing reservoir pressure, then it any of the auxiliary reservoirs on the cars leak, such leakage will permit the higher brake pipe pressure to cause an undesired release the brakes on all cars having an auxiliary'reservoir subject to such leakage.

As hereinbefore described, the inilial slow rate of reduction in equalizing reservoir pressure is governed by the flow capacity oi the choked port 50 in the plug valve 1 and the faster rate of the second. portion of the reduction is governed, by the combined flow capacities of the choked port 50 and the port 31 through the valve stem Since the rate of etl'ecting the brake pipe rediu-tion can be increased as the train length is decreased, on account of the (lCUlLtlL-iU in severity of the slack action, then for a shorler train, the plug valve 4-8 is turned until the handle 49 is in the position indicated by the line 53, in which position the choked port 51 in the plug valve 48 connects passages 28 and 52. The choked port 51 has grealcr flow area than the choked port and consequently permits a faster rate of drop in equalizing reservoir pressure.

If it is desired to manually ellcct a reduction in brake pipe pressure, when the train control apparatus is in the release condition, as shown in the drawing, the brake valve handle 6 is moved to service position in the usual manner. In service position, the connection between the feed valve passage 66 and passage (38 leading to the brake pipe 10, is cut oil through the port 67 in the rotary valve 5, so as to prevent further flow oi fluid from the feed valve device 3 to the brake pipe 10, and at lhe e or the fluid in both oi? said reservoirs permitted to reduce by flow through the atmospheric port 77. Such reduction is ell'ective in the equalizing diaphragm chamber 8, which causes the equal .iszing valve mechanism to operate and permit a rediuztion in brake pipe pressure, in the same manner as hereiubefore described for a train control application of the brakes.

in manually eii'ecting a brake application, the reduction re aliating valve inechanisn'i does not operate as when a train control. application of the brakes is effected, because the reduction regulating reservoir pressure, eii 'ective in the diaphragm chan'iber 19, reduces with the equalizing reservoir pressure, which is eiiective in the diaphragm chamber 21. The fluid pressures thus remain. substau tially equal on the opposite sides of the reduction regulating valve diaphragm 18, so that spring 25 holds such diaphragm in its normal position, against the stop 81.

The capacity of the atmospheric port 2"? so pioportioncd to the combined volumes ot the etpializinp; reservoir and reduction i'egrulating reservoir as to e'llect adecrease in the pressure in such miervoirs at the same rate ah with the usual locomotive brake equipment.

in chin-sing the brake pipe, it is undesir-able to have the equalizing reservoir be come charged to a higher pressure than the pressure in the brake pipe, because it while charging); it is desired to manually ellect a brake pipe reduction or the train control apparatus operates to eiiect a reduction in brake pipe pressure, the higher eqauilizing reservoir pressure has to be reduced to no al the lower brake pipe pressure, before a re duction in hraire pipe pressure can be started, which causes a delay in effecting a brake pipe reduction. in order to prevent the equalizing reservoir from becoming charged to a higher pi .ssure than in the bral-te pipe, the etpuilizinp; rtservoir normally cons-och ed to the seat of the equalizing slide valve 12 by way of pipe and passage 23, cavity 73 in the application slide valve, passage 74-, spring chamber 38, valve chamber 34: and

passage 35, so that ii. the equalizing reservoir pressure starts to become greater than the brake pipe pressure, such equalizing reservoir pressure causes the equalizing valve mechanism to shift the slidevalve 12 downwardly and uncover passage 35. This perinits fluid under pressure to flowfrom the equalizing reservoir to brake pipe 10 tl'u'ough the valve chamber 9, so that as a result the pressures in the equalizing reservoir and brake pipe are always substantially equal in charging.

As shown in the drawing, the equalizing reservoir pressure can be reduced at only two different rates, as governed by the different size of the choked ports 50 and 51 in the ping valve d8. it might be desirable to have more than two choked ports through the plug valve, so as to provide for more than two rates of rcduring equalizing reservoir pressure.

lVhjilo one illustrative en'lbodinwnt of the invention has been described in detail, it is not our intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described our invention, what we claim as new and desire to secure by lat-rt tors Patent, ist

1. In a fluid pressure brake, the conibination with a brake pipe and an equalizing reservoir, of a valve device subject to the op posing pressures of the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for eilt'ecti'i a reduction in, brake pipe pressur a and means for initially venting fluid under pres sure from said reervoi r at one rate to (iperate said valve device to vent fluid from the brake pipe and then at a faster rate.

2. In a fluid pressure brake, the combination with a brake pipe and an equaliziup, reservoir, of a valve device subject to the opposing pressures oi the brake pipe and equalizing}; reservoir and operated upon a reduction in equalizing reservoir pressure for etiect-i'iur a rtuluction in brake pipe pressure, means ior initially venting fluid under pres-- sure from said reservoir at one rate, and means operatei l. upon a predetermined reduction in pressure in said reservoir for venting fluid from said reservoir at a more rapid rate.

3. In a fluid pressure brake, the combination with a brake pipe and an equalizing reservoir, of a valve device subjectto the opposing; pressures of the brake pipe and rtplaliziug reservoir and operated upon a reduction in equalizing); reservoir pressure For effecting a reduction in brake pipe pressure, means for initially venting fluid. under pressure from said reservoir at one rate, and means operated upon a predetermined reduction in pressure in. said reservoir for also venting fluid from said reservoir.

4. In a fluid iiressure brake, the combina- 'tion with a brake pipe. and an equalizing; reservoir, of a valve device subject to the opposing pressures of the brake, pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for eil'ectiue a reduction inbrake pipe pressure,

ineans for initially venting fluid under pres sure from said reservoir at one rate, and

means operated upon a predetermined reduction in pressure 111 said reservoir for opening; an additional communication through winch had is vented ironi said reservolr.

Under some conditions,

5. In fluid pressure brake, the combination With a brake pipe and an equalizing reservoir, of'a valvedevice subject to the opposing pressures of the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for effecting 3, 1'8 ClllCt10Il'1I1 brake pipe pressure,

means for initially venting fluid from said reservoir a reduction regulating reservoir, and means sub ect to the opposing pressures ofthe equalizing reservoir and the reduction reduction in equalizing reservoir pressure regulating reservoir and operated upon a predetermined reduction in pressure inthe equalizing reservoir for also venting fluid from the equalizing reservoir.

'' 6. In a fluid pressure brake, the combina- "tion wvith a brake pipe andan equalizing reservoir, of a valve device subject to the opposing pressures-of the-brake pipe and equalizing reservoir and operated upon a for effecting a reduction in brake pipe pressure, a reduction reservoir, means for venting. fluid from said equalizingreservoir to said: reduction reservoir, a reduction regulating reservoir, and means subject to the opposing pressures of the equalizing reservoir and the reduction regulating reservoir and operated 'upon a predetermined reduction in pressure intlrc equalizing reservoir for vent- 'ing fluid from theequalizing reservoir.

7; In a fluid pressure brake, the combination with a brake pipe and an equalizing reservoir-,of avalvo device subject to the opposing pressures of the brake pipe and -equalizing reservoir and operated upon a re- 'duction in equalizing reservoir pressure eiiecting a reduction in brake pipe pressure, means for efi'ecting a reduction in equalizing reservoir pressure 111: two stages, and means operativeupona reduction in'brake pipe pressure below that in the equalizing reservoir for supplying fluidunder pressure to the brake pipe. only during the period the first stage of reduction is beingefi ected.

8. In a fluid pressure brake, the combination with abrake pipe and: an equalizing 1 reservoir, of a valve device subject to the opposing pressures of 'the bralce pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for effecting a reductioninibrake pipe pres sure, means .for effecting a reduction in {equalizing reservoir pressure in two stages,

pressure for preventing the supply of fluid to the brake pipe.

- 9 In a fluid pressure brake, the combination With a brake pipe and an equalizing reservoir, of avalve device subject to the supplying opposing pressures of the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for effecting a reduction in brake pipe pres sure, means for ciiecting a reduction in equalizing reservoir pressure in two stages, means operative upon the brake pi pc pressure reducing faster than the equalizing reservoir pressure is reducing for supplying: fluid under pressure to the brake pipe, and valve means ope]. tive upon a predetermined reduction in p1 re in the equalizing reservoir for )reventing the supply oi. lluid to the brake pipe.

10. In a fluid pressure brake, the co1uhi-- nation vith a brake pipe and an equalizing -rvoir, or a vahrc device subject to the sing pressures of the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for effecting a reduction in brake pipe pressure, means for eil'ect ng a reduction in equalizing reservoir pressure in two stages, nieans operative upon me brake pipe prc sure reducing faster than the cqualiz reservoir pressur is reducing for supplyi fluid under lJI'Qx we to the brake pipe, and valve means operative upon a predctermined reduction in pressure in the ezpializimg reservoir for cuttiinr oll communicai'ion through Whirh fluid under pressure supplied to the brake pipe.

11. In a fluid pressure brake, the combination with a brake pipe, o means tor lirst eiiecting a reduction in brake pipe pressure at one rate, means for thcn effecting a reduction in brahe pipe pressure at a 'i'a:-.:ler rate. and means supplying fluid under pres sure to the brake pipe to compensate for leakage from the brake pipe only during the reduction in brake pipe presiau-e at the slow rate.

12. In a. fluid pressure brake, the combination with a brake pipe and equalizing reservoir, of means OpOlftiOtl upon a rrducs tron in pressure in the equalizing reservoir for ell ecting a reduction in brake pipe pressure, means for first eil'ccting a reduction in equalizing reservoir pressure at one rate, means for then effecting a reduction in equalizing reservoir pressure taster rate, and means for supplying fluid under pressure to the brake pipe to compensate tor leakage from the brake pipe, only while the first reduction in equalizing reservoir pressure is being effected.

In a fluid pressure brake. the combination with a brake pipe and equalizing reservoir, of a valve device operated upon a reduction in pressure in said equalizing reservoir for effecting a. reduction in brake pipe pressure and manually operalcd means for varying the rate at which the pressure in the equalizing l'GSOl'VO'll' is reduced.

l i. In a fluid pressure brake, the combillll) Ill) nation with a brake pipe and equalizing reservoir, of a valve device operated upon a. reduction. in pressure in said equalizing reservoir tor eflecting a reduction in brake pipe pressure and a manually operated valve for establishing communication in one position for venting fluid fl rorn the eqiuilizing reservoir at one rate and for establishing connnunication in another position for venting fluid from the equalizing reservoir at another rate.

15. In a fluid pressure brake, the co1nbination with a brake pipe and equalizing reservoir, of a valve device operated upon a re duction in equalizing reservoir .)1.'essure for venting fluid troni'the brake pipe, means for wanting fluid from the equalizing reservoir, and a n'lanually operated valve for establishing connuunication through Which fluid is vented from the equalizirr' reservoir, said valve h aving different positions in which the rate is varied at which fluid is vented from the equalizing reservoir.

16. In a fluid prei-isltlre brake, the combina tion With a brake pipe and. equalizing res-- ervoir, of a valve device operated upon a reduction in equalizing reservoir pressure for venting fluid :l'roin the brake pipe, a reduction reservoir, means tlior venting fluid. from the equalizing reseriuiir to the reduction reservoir, and manually operated valve means for varying the rate at which fluid vented from the equalizing reservoir to the reduction reservoir.

1.7, in a fluid pressure brake, the combination with a brake pipe and equalizing reservoir, of a valve device subject to the opposing pressures of the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for venting fluid from. the brake pipe, incans normally operative to connect the equalizing reservoirs to the brake pipe upon an increase in equalizing reservoir pressure above that in the brake pipe, a source of fluid under pressure, and means operative upon eflecting a reduction in brake pipe pressure for supplying fluid from said source to the brake pipe in case the equalizing reservoir pressure exceeds brake pipe pressure.

18. In a fluid pressure brake, the combination with a brake pipe and equalizing reservoir, of a valve device subject to the opposing pressures of the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for venting fluid from the brake pipe, said valve device being operative u pon an increase in equalizing reservoir pressure above that in the brake pipe for connecting a passage with the brake pipe, a source oi fluid under pressure, and means having one position in which. the equalizing reservoir is connected to said passage and another position in which said source of fluid under pressure is connected. to said passage.

19. In a fluid. pressure brake, the coinbination with a brake pipe and. equalizing reservoir, of a valve device suhjectito the opposing pr arcs of the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir pressure for venting fluid "from the brake pipe, said valve device being operative upon an increase in equalizing reservoir pressure above that in the brake pipe for connecting a passa e with the brake pipe, at source 0t fluid under pressure, and an application valve device adapted in. release position to connect the equalizing reservoirvvith said passage and in application position to connect said source of fluid under pressure to said passage.

20. In a fluid pressure hr: he, the combination with a brake pipe and ci'iual'iiing reservoir, ot a valve device subject to the opposing pressures ()Tii' the brake pipe and equalizing reservoir and operated upon a reduction in equalizing reservoir prcssi'lre :ior venting fluid. from the brake pipe, said. valve device being operative upon. an increase in equalizing reservoir pressure above that in the brake pipe for connecting a passage with the brake pipe, at source oil fluid under pressure, and an application 'alve device adapted in release position to connect the equalizing reservoir to said passage and in application position to establish counnunication through which fluid. vented from the equalizing reservoir and also to. connect said source of fluid. under pressure to said passage.

In testinmny whereof We have hereunto set our hands this 28th day of November,

THOMAS H. THOll lAlii. Cllaillllla A. NELSON. 

